Designers of internal combustion engines are continually seeking to develop hardware and control strategies which improve fuel efficiency and reduce exhaust emissions. As an example, designers of engines using combustion-ignition strategies, i.e., diesel engines, have developed sophisticated injection systems which execute multiple fuel injection pulses within each cylinder during each combustion cycle. Such engines employ expensive piezoelectric technology, and since diesel engines do not employ spark ignition, there is no risk of having the multiple injection pulses interact with an arc from a spark plug. Some wall-guided gasoline spark-ignition, direct injection (SIDI) engines employ multiple fuel injection pulses using solenoid-operated swirl-spray injectors. Such injection pulses are typically selectively employed to achieve accelerated warm-up and light-off of exhaust aftertreatment devices, as well as to facilitate transition in engine operation between a stratified operating regime and a homogeneous engine operating regime. The period between two injection pulses in such engines is typically in a range of 180 crank-angle degrees (typically around 15 milliseconds at 2000 rpm). This time period is considered too large to have any opportunity for both fuel charges to interact with a spark arc.
What is needed is a system for control of an SIDI engine which provides multiple fuel injection pulses to control ignition and combustion processes within the combustion chamber, thus reducing combustion variability, improving fuel efficiency and reducing engine-out emissions.